GENERAL INFORMATION

This README.txt file was updated on the 17th February 2025 

A. Paper associated with this archive
Cardoso GC & Batalha HR (2025) A female-specific color signal? Black-mottled bills indicate breeding in female common waxbills. American Naturalist
Brief abstract: Female ornamentation is common in birds but usually resembles that of males. In contrast to this general pattern, here we show that the red bill of wild adult common waxbills (Estrilda astrild) often becomes mottled with black when females breed. This color change is not explained by reallocation of red carotenoid pigments away from the bill, but requires deposition of melanin pigments. The change is very noticeable and makes female bills resemble the black bill of nestlings and fledglings. Perhaps this color change exploits useful innate responses of males towards nestlings, such as ceasing mating-related behavior and initiating parental care. Unlike the vast majority of female signals and ornaments black-mottled bills are not derived from a male trait, but they are derived from a nestling trait, in accordance with the idea that color signals often evolve using pre-existing developmental paths.

B. Originators
Gonçalo C. Cardoso1,2, Helena Reis Batalha1
1. CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
2. BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, Vairão, Portugal

C. Contact information
Gonçalo C. Cardoso
CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
gcardoso@cibio.up.pt

D. Dates of data collection
2010-2011

E. Geographic Location(s) of data collection
Portugal

F. Funding Sources
Fundação para a Ciência e a Tecnologia grant PTDC/BIA-BEC/098414/2008


ACCESS INFORMATION

1. Licenses/restrictions placed on the data or code
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication

2. Data derived from other sources
Not applicable.

3. Recommended citation for this data/code archive
Cardoso GC & Batalha HR (2025) Replication Data for: A female-specific color signal? Black-mottled bills indicate breeding in female common waxbills. American Naturalist, Dataverse Digital Repository.


DATA & CODE FILE OVERVIEW
This data repository consist of 1 data file, 1 analyses file, and this README document, with the following filenames and variables:

    1. Dataset.txt
The dataset lists common waxbills that were captured, sexed molecularly and not aged as juveniles, indicating whether the bill was mottled black, and whether they had a brood patch. Dates and sites of capture are also indicated.
- Bird_ID: Leg ring number for each bird.
- Sex: F (female) or M (male).
- Bill_mottled_black: Yes or No.
- Brood_patch: Yes or No.
- Site: Name of field work site.
- Date: Date of capture.

    2. Tests.xlx
Spreadsheet with Chi^2 test results, following the order reported in the Results section of the original article. Chi^2 test formulae from Zar (1996).


SOFTWARE VERSIONS
Not applicable.


REFERENCES
Zar, J.H. (1996) Biostatistical analyses, third edition. Prentice Hall.
